Master C# Programming From Scratch

Operators

An operator in C# is a symbol that tells the compiler to perform specific mathematical, logical, or data manipulations on operands (variables or values).

C# provides a rich set of built-in operators. Below are the primary categories of C# Operators

1. Arithmetic Operators

   Used to perform common mathematical computations on numeric types

   • + (Addition): Adds two values.
   • - (Subtraction): Subtracts one value from another.
   • * (Multiplication): Multiplies two values.
   • / (Division): Divides one value by another.
   • % (Modulus): Returns the division remainder.
   Static Code Layout Reference

   int a = 10;
   int b = 3;
   
   Console.WriteLine(a + b); // Output: 13
   Console.WriteLine(a - b); // Output: 7
   Console.WriteLine(a * b); // Output: 30
   Console.WriteLine(a / b); // Output: 3 (Integer division drops decimal part)
   Console.WriteLine(a % b); // Output: 1 (Remainder of 10 / 3)
   

2. Relational (Comparison) Operators

   Used to compare two values. These always return a boolean result (true or false)

   • == (Equal to): Checks if two values are equal.
   • != (Not equal to): Checks if two values are not equal.
   • > (Greater than): Checks if the left value is greater than the right.
   • < (Less than): Checks if the left value is less than the right.
   • >= (Greater than or equal to): Checks left value is greater than or equal to the right.
   • <= (Less than or equal to): Checks left value is less than or equal to the right.
   Static Code Layout Reference

   int x = 5;
   int y = 10;
   Console.WriteLine(x == y); // Output: False
   Console.WriteLine(x != y); // Output: True
   Console.WriteLine(x > y); // Output: False
   Console.WriteLine(x < y); // Output: True
   Console.WriteLine(x >= 5); // Output: True
   

3. Logical Operators

   Used to combine multiple boolean conditions or expressions

   • && (Logical AND): Returns true if both statements are true.
   • || (Logical OR): Returns true if at least one statement is true.
   • ! (Logical NOT): Reverses the logical state (turns true to false and vice versa)
   Static Code Layout Reference

   bool isSunny = true;
   bool isWarm = false;
   
   Console.WriteLine(isSunny && isWarm); // Output: False
   Console.WriteLine(isSunny || isWarm); // Output: True
   Console.WriteLine(!isSunny); // Output: False
   

4. Assignment Operators

   Used to assign values to variables. This includes compound assignments which combine arithmetic operations with an assignment.

   • = (Simple Assignment): Assigns right value to left variable.
   • += (Add and assign): Shorthand for x = x + y.
   • -= (Subtract and assign): Shorthand for x = x - y
   • *= (Multiply and assign): Shorthand for x = x * y.
   • /= (Divide and assign): Shorthand for x = x / y
   Static Code Layout Reference

   int score = 10; // Simple assignment
   
   score += 5; // Equivalent to score = score + 5; (score is now 15)
   score -= 2; // Equivalent to score = score - 2; (score is now 13)
   score *= 2; // Equivalent to score = score * 2; (score is now 26)
   Console.WriteLine(score); // Output: 26
   

5. Increment and Decrement Operators

   Unary operators used to increase or decrease a variable's value by exactly

   • ++ (Increment): Increases value by 1.
   • -- (Decrement): Decreases value by 1
   Static Code Layout Reference

   int energy = 5;
   
   energy++; // Postfix increment (energy becomes 6)
   Console.WriteLine(energy); // Output: 6
   
   --energy;// Prefix decrement (energy becomes 5)
   Console.WriteLine(energy); // Output: 5
   

6. Ternary (Conditional) Operator

   A shorthand alternative to the if-else statement. It operates on three operands: condition ? expression_if_true : expression_if_false

   Static Code Layout Reference

   int age = 20;
   string status = (age >= 18) ? "Adult" : "Minor";
   
   Console.WriteLine(status); // Output: Adult
   

7. Null-Coalescing Operators

   Operators designed to cleanly handle variables that might hold null values

   • ??: Returns the left-hand operand if it is not null; otherwise, it returns the right-hand operand.

   • ??=: Assigns the right-hand value to the left-hand variable only if the left-hand variable is currently null

   Static Code Layout Reference

   string? name = null;
   
   

   // Use fallback if name is null

   string displayName = name ?? "Guest"; Console.WriteLine(displayName); // Output: Guest
   
   

   // Assign value only if null

   name ??= "Alice"; Console.WriteLine(name);

   // Output: Alice